"God is spirit, and those who worship him must worship in spirit and truth."

— John 4:24 ESV

…a most pure spirit, invisible, without body, parts, or passions, who only hath immortality, dwelling in the light which no man can approach unto…1

In today's evangelicalism, God's love is commonly identified as His foundational character. Contemporary Reformed believers have God's holiness as the most foundational attribute. During Reformed Orthodoxy, God's Simplicity, or the Simplicitas Dei, was a crucial element in the doctrine of God, or Classical Theism, and a necessary attribute of God. This doctrine was considered essential to maintaining Christian monotheism and the doctrine of the Trinity.2

The phrase "without parts," in reference to God found in the Reformed Confession, is related to the doctrine of divine simplicity. Beeke and Smalley, commenting on Christ's word in John 4:24, write,

God's simplicity means that he has no parts, and his attributes and essence are all one in him. Christ did not say that God has a spirit, but "God is a Spirit."3

This doctrine was upheld throughout the early, high, and late orthodoxy periods, though not always with the same emphasis.4 Theologians in these eras understood that God is not a composite being grounded in the truth that He is the ultimate Spirit. Theologians of these periods used the concept of divine simplicity as a way to support the doctrine of the Trinity and argued it was essential for an orthodox understanding of God.

Here's how the understanding of "without parts" or divine simplicity is represented in the sources across these periods:

Early Orthodoxy (c. 1565–1640)5

Early orthodox theologians affirmed that God is "without parts", meaning that God is not composed of different elements. Theologians in this period used Aristotelian philosophical categories to articulate the doctrine. Amandus Polanus (1561–1610), for example, denies distinctions in God between matter and form, genus and species, substance and accidents, act and potency, and essence and existence.6

While the concept was present in this period, it wasn't always discussed as a separate attribute in theological systems, nor was it always given the same prominence. However, Girolamo Zanchi (1516–1590) considered the doctrine of Divine Simplicity as necessary for orthodoxy and essential for understanding the names of God:

When I speak of and name God, I understand him to be eternal, invisible, immortal, most simple, most perfect in all ways.7

Therefore what did the Apostle understand by the term "Spirit of holiness" except his divine nature? For we read in John that, "God is Spirit." Here, with the word "Spirit," a most simple and incorporeal thing — that is, the divine nature — is understood and is contrasted with the body.8

High Orthodoxy (c. 1640–1685/1725)9

Theologians continued to affirm divine simplicity, often repeating and defending the formulations of the early Orthodox period. During this period, there was a tendency to provide more detailed explanations of the doctrine of divine simplicity. High orthodoxy is characterized by a more broadly developed and discursive system of theology, incorporating expanded polemical argumentation and elaboration of existing ideas.

High orthodox theologians, like those before them, rejected the idea that the divine essence could be divided into parts. They affirmed that the attributes of God are not distinct "things" within God, but rather are "different conceptions of the same thing."10

They used this concept to safeguard the doctrine of the Trinity from potential misunderstandings, while still affirming that God was "without parts." The Simplicitas Dei is deduced from God's oneness. Stephen Charnock is known during this era:

Where there is the greatest unity, there must be the greatest simplicity; but God is one. As he is free from any change, so he is void of any multitude (Deut. 6:4): "The Lord our God is one Lord."11

Late Orthodoxy (c. 1685/1725–1790)12

Theologians in this period continued to uphold divine simplicity as a core tenet of Reformed theology. They maintained that God is not a compounded or composite being and that there is no "accident" in God. Theologians in this period engaged with new challenges from rationalist philosophy, which did not always accept the traditional understanding of God's nature. They sought to define their position against the challenges to the doctrine. Some theologians of the late Orthodox era, like Daniel Wyttenbach (1746–1829), explicitly affirmed that "God is ens simplex and that, therefore, in God there is no accident."13 Another is Bernardinus De Moor who wrote the most extensive Didactico-Elenctic Theology, which argued against the possibility of multiple deities:

Simplicity follows, which again is a more Negative term, since one calls that Simple which is without composition; Positively it is called Unity, that is, the altogether perfect Unity of the Divine Essence and Attributes, excluding all Real Composition.14

Conclusion

Across all three periods, the doctrine of divine simplicity, and the idea that God is "without parts," was fundamental. While there were variations in emphasis and philosophical engagement, the core belief that God is not a composite being remained constant.

The doctrine of Divine Simplicity played an important role in the development of Reformed Orthodoxy against various challenges to God's essence and the Trinity. This doctrine, among others, highlights that God is not like us, and worthy of the highest praise! He is the Holy Simple Other, and He condescends to reach sinners in Christ for His glory and our good.

To God be the glory!

Footnotes

  1. 1689 Second London Baptist Confession of Faith, Chapter 2: Of God and of the Holy Trinity. ↩

  2. Minich, Joseph, and Onsi A. Kamel. The Lord Is One: Reclaiming Divine Simplicity. Leesburg, Virginia: The Davenant Press, 2019. "The early Reformed theologians may not have developed an in-depth doctrine of divine simplicity, but they did see it as essential for maintaining Christian monotheism and the Christian doctrine of the Trinity." ↩

  3. Beeke and Smalley, Reformed Systematic Theology, ePub ed., ch. 33. ↩

  4. Muller, Prolegomena to Theology, ch. 1. The Reformed orthodox theologians reiterate God's simplicity in continuity with the Catholic tradition and under the weight of biblical exegesis. If one divides the epoch of orthodoxy into the early (c. 1565–1640), high (c. 1640–85) and late (c. 1685–1725) eras, the Reformed theologians in each of the three distinguishable periods are unified on the essential content of the doctrine of divine simplicity while still showing some diversity of opinion on finer points. ↩

  5. Among the Early Orthodox theologians are Zacharias Ursinus, Caspar Olevianus, Jerome Zanchi, Lambert Daneau, Theodore Beza, Francis Junius, William Perkins, Amandus Polanus, William Ames and J. H. Alsted, and Johannes Maccovius. Muller, "The eras and phases of Protestant orthodoxy," ch. 1. ↩

  6. Duby, Steven J. Divine Simplicity. Bloomsbury Publishing, 2015. p. 23. ↩

  7. Zanchi, Girolamo. On the Triune Elohim: Eternal Father, Son, and Holy Spirit, One and the Same Jehovah. 1572. Edited by Ben Merkle, The Davenant Trust and The Acton Institute. p. 37. ↩

  8. Zanchi, p. 124. ↩

  9. Muller lists the following theologians during the High Orthodox period: Johannes Cocceius, Samuel Maresius, Andreas Essenius, Gisbertus Voetius, Friedrich Spanheim the elder, Marcus Friedrich Wendelin, Franz Burman, Francis Turretin, Edward Leigh, Matthew Poole, John Owen, and Stephen Charnock. Muller, Prolegomena to Theology, ch. 1. ↩

  10. Muller, Essence and Divine Attributes, ePub ed., 2.4. ↩

  11. Charnock, Stephen. The Existence and Attributes of God (2-Volume Set). Crossway, 2022. ePub ed., ch. 3. ↩

  12. Late Orthodox theologians include Daniel Wyttenbach, Johann Friedrich Stapfer, Herman Venema, John Gill, Alexander Comrie, John Brown of Haddington, and Bernhardus de Moor. ↩

  13. As quoted by Richard Muller, Essence and Divine Attributes, ePub ed., 2.4. ↩

  14. Dilday, Dr. "De Moor IV:23: Arguments for the Simplicity of God: A Priori." From-Ref-To-Ref, 14 Dec. 2018. Emphasis in the original. ↩